1. Field of the Invention
The present invention relates to an image-taking apparatus which uses an image-pickup device to take image information and to a monitoring system which uses the image-taking apparatus.
2. Description of Related Art
Locating service which uses the GPS (Global Positioning System) has been provided as aid service for lost children, wandering demented elderly people, and visually handicapped people.
This is service in which a person to be aided such as a child or an elderly person carries a GPS terminal (such as a dedicated terminal or a cellular phone having a GPS function) and the current position of the person is determined on the basis of the positions of GPS satellites and the time to rescue him/her.
Only the use of the GPS or the like to take positional information, however, cannot provide knowledge about circumstances surrounding the person to be aided. Specifically, the aforementioned service has a problem that it is not possible to determine from the positional information on a map whether or not the person to be aided is in a situation in which he/she needs emergent help or whether or not he/she is at a position which can be easily found.
To address this, Japanese Patent Application Laid-Open No. 2001-128149 has proposed a system which is particularly suitable for walking support of visually handicapped people by using an image-taking apparatus such as a video camera and a PHS terminal in order to eliminate the aforementioned disadvantage of the aid system which only takes positional information with the GPS or the like. The patent has proposed a support system in which a visually handicapped person carries an image-taking apparatus such as a video camera to transmit taken image to a support center where an operator provides walking guidance with his/her voice while seeing an image monitor installed therein, as well as a walking guidance support system which utilizes the determination of the current position through the GPS and guidance by an operator in a support center.
The aforementioned patent has proposed Embodiment 1 employing a PHS terminal provided with a video camera in which the video camera and the PHS terminal are formed into an integral unit to allow a user (a visually handicapped person) to take image over a wide area by moving the terminal in front-to-back and right-to-left directions. The patent also has proposed Embodiment 2 in which a video camera and a PHS terminal are separately formed and the video camera is connected to the PHS terminal through a cable to allow a user to take image by the video camera hung from his/her neck.
In Embodiment 1 therein, however, the user can take image only by moving the PHS terminal with the video camera in front-to-back and right-to-left directions. Thus, it is not suitable for use by a lost child (especially an infant) or a wandering elderly person.
In Embodiment 2, the handling of the cable is cumbersome when the video camera is hung from his/her neck. Especially for an infant, the video camera and the cable hung from his/her neck interfere with the movement of his/her body, so that he/she may take off the video camera from his/her body or disconnect the cable to make normal operation of the system impossible.
Both when a visually handicapped person uses the system and when a lost child or a wandering elderly person uses the system, the system proposed in the aforementioned patent must have, in the image-taking apparatus, a so-called super wide-angle (fish-eye) lens which allows image taking at a wide field angle corresponding to the visual field of both eyes of a human (generally, 60 degrees in the vertical direction and at least 120 to 160 degrees in the horizontal direction) in order to effectively function the system.
As shown in FIG. 10, however, such a super wide-angle lens 1000 is formed of as much as 8 lens units, and thus very heavy and considerably large in lens length. As a result, the system proposed in the aforementioned patent is likely to be inappropriate for actual use.